//===-- BasicBlock.cpp - Implement BasicBlock related methods -------------===//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file implements the BasicBlock class for the VMCore library.
#include "llvm/Type.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/LeakDetector.h"
+#include "llvm/Support/Compiler.h"
#include "SymbolTableListTraitsImpl.h"
#include <algorithm>
using namespace llvm;
+inline ValueSymbolTable *
+ilist_traits<Instruction>::getSymTab(BasicBlock *BB) {
+ if (BB)
+ if (Function *F = BB->getParent())
+ return &F->getValueSymbolTable();
+ return 0;
+}
+
+
namespace {
/// DummyInst - An instance of this class is used to mark the end of the
/// instruction list. This is not a real instruction.
- struct DummyInst : public Instruction {
+ struct VISIBILITY_HIDDEN DummyInst : public Instruction {
+ // allocate space for exactly zero operands
+ void *operator new(size_t s) {
+ return User::operator new(s, 0);
+ }
DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) {
// This should not be garbage monitored.
LeakDetector::removeGarbageObject(this);
}
- virtual Instruction *clone() const {
+ Instruction *clone() const {
assert(0 && "Cannot clone EOL");abort();
return 0;
}
- virtual const char *getOpcodeName() const { return "*end-of-list-inst*"; }
+ const char *getOpcodeName() const { return "*end-of-list-inst*"; }
// Methods for support type inquiry through isa, cast, and dyn_cast...
static inline bool classof(const DummyInst *) { return true; }
// Explicit instantiation of SymbolTableListTraits since some of the methods
// are not in the public header file...
-template class SymbolTableListTraits<Instruction, BasicBlock, Function>;
+template class SymbolTableListTraits<Instruction, BasicBlock>;
-BasicBlock::BasicBlock(const std::string &Name, Function *Parent,
+BasicBlock::BasicBlock(const std::string &Name, Function *NewParent,
BasicBlock *InsertBefore)
- : Value(Type::LabelTy, Value::BasicBlockVal, Name) {
- // Initialize the instlist...
- InstList.setItemParent(this);
+ : Value(Type::LabelTy, Value::BasicBlockVal), Parent(0) {
// Make sure that we get added to a function
LeakDetector::addGarbageObject(this);
if (InsertBefore) {
- assert(Parent &&
+ assert(NewParent &&
"Cannot insert block before another block with no function!");
- Parent->getBasicBlockList().insert(InsertBefore, this);
- } else if (Parent) {
- Parent->getBasicBlockList().push_back(this);
+ NewParent->getBasicBlockList().insert(InsertBefore, this);
+ } else if (NewParent) {
+ NewParent->getBasicBlockList().push_back(this);
}
+
+ setName(Name);
}
if (getParent())
LeakDetector::addGarbageObject(this);
- InstList.setParent(parent);
+ // Set Parent=parent, updating instruction symtab entries as appropriate.
+ InstList.setSymTabObject(&Parent, parent);
if (getParent())
LeakDetector::removeGarbageObject(this);
getParent()->getBasicBlockList().erase(this);
}
+/// moveBefore - Unlink this basic block from its current function and
+/// insert it into the function that MovePos lives in, right before MovePos.
+void BasicBlock::moveBefore(BasicBlock *MovePos) {
+ MovePos->getParent()->getBasicBlockList().splice(MovePos,
+ getParent()->getBasicBlockList(), this);
+}
+
+/// moveAfter - Unlink this basic block from its current function and
+/// insert it into the function that MovePos lives in, right after MovePos.
+void BasicBlock::moveAfter(BasicBlock *MovePos) {
+ Function::iterator I = MovePos;
+ MovePos->getParent()->getBasicBlockList().splice(++I,
+ getParent()->getBasicBlockList(), this);
+}
+
TerminatorInst *BasicBlock::getTerminator() {
if (InstList.empty()) return 0;
return dyn_cast<TerminatorInst>(&InstList.back());
}
-const TerminatorInst *const BasicBlock::getTerminator() const {
+const TerminatorInst *BasicBlock::getTerminator() const {
if (InstList.empty()) return 0;
return dyn_cast<TerminatorInst>(&InstList.back());
}
+Instruction* BasicBlock::getFirstNonPHI()
+{
+ BasicBlock::iterator i = begin();
+ // All valid basic blocks should have a terminator,
+ // which is not a PHINode. If we have invalid basic
+ // block we'll get assert when dereferencing past-the-end
+ // iterator.
+ while (isa<PHINode>(i)) ++i;
+ return &*i;
+}
+
void BasicBlock::dropAllReferences() {
for(iterator I = begin(), E = end(); I != E; ++I)
I->dropAllReferences();
return (PI == E) ? ThePred : 0 /*multiple preds*/;
}
-// removePredecessor - This method is used to notify a BasicBlock that the
-// specified Predecessor of the block is no longer able to reach it. This is
-// actually not used to update the Predecessor list, but is actually used to
-// update the PHI nodes that reside in the block. Note that this should be
-// called while the predecessor still refers to this block.
-//
+/// removePredecessor - This method is used to notify a BasicBlock that the
+/// specified Predecessor of the block is no longer able to reach it. This is
+/// actually not used to update the Predecessor list, but is actually used to
+/// update the PHI nodes that reside in the block. Note that this should be
+/// called while the predecessor still refers to this block.
+///
void BasicBlock::removePredecessor(BasicBlock *Pred,
bool DontDeleteUselessPHIs) {
assert((hasNUsesOrMore(16)||// Reduce cost of this assertion for complex CFGs.
find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) &&
- "removePredecessor: BB is not a predecessor!");
+ "removePredecessor: BB is not a predecessor!");
if (InstList.empty()) return;
PHINode *APN = dyn_cast<PHINode>(&front());
// br Loop ;; %x2 does not dominate all uses
//
// This is because the PHI node input is actually taken from the predecessor
- // basic block. The only case this can happen is with a self loop, so we
+ // basic block. The only case this can happen is with a self loop, so we
// check for this case explicitly now.
- //
+ //
unsigned max_idx = APN->getNumIncomingValues();
assert(max_idx != 0 && "PHI Node in block with 0 predecessors!?!?!");
if (max_idx == 2) {
// Okay, now we know that we need to remove predecessor #pred_idx from all
// PHI nodes. Iterate over each PHI node fixing them up
PHINode *PN;
- for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ++II)
+ for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ) {
+ ++II;
PN->removeIncomingValue(Pred, false);
+ // If all incoming values to the Phi are the same, we can replace the Phi
+ // with that value.
+ Value* PNV = 0;
+ if (!DontDeleteUselessPHIs && (PNV = PN->hasConstantValue())) {
+ PN->replaceAllUsesWith(PNV);
+ PN->eraseFromParent();
+ }
+ }
}
}
/// splitBasicBlock - This splits a basic block into two at the specified
/// instruction. Note that all instructions BEFORE the specified iterator stay
-/// as part of the original basic block, an unconditional branch is added to
+/// as part of the original basic block, an unconditional branch is added to
/// the new BB, and the rest of the instructions in the BB are moved to the new
/// BB, including the old terminator. This invalidates the iterator.
///
-/// Note that this only works on well formed basic blocks (must have a
+/// Note that this only works on well formed basic blocks (must have a
/// terminator), and 'I' must not be the end of instruction list (which would
/// cause a degenerate basic block to be formed, having a terminator inside of
-/// the basic block).
+/// the basic block).
///
BasicBlock *BasicBlock::splitBasicBlock(iterator I, const std::string &BBName) {
assert(getTerminator() && "Can't use splitBasicBlock on degenerate BB!");
- assert(I != InstList.end() &&
- "Trying to get me to create degenerate basic block!");
+ assert(I != InstList.end() &&
+ "Trying to get me to create degenerate basic block!");
- BasicBlock *New = new BasicBlock(BBName, getParent(), getNext());
+ BasicBlock *New = BasicBlock::Create(BBName, getParent(), getNext());
// Move all of the specified instructions from the original basic block into
// the new basic block.
New->getInstList().splice(New->end(), this->getInstList(), I, end());
// Add a branch instruction to the newly formed basic block.
- new BranchInst(New, this);
+ BranchInst::Create(New, this);
// Now we must loop through all of the successors of the New block (which
// _were_ the successors of the 'this' block), and update any PHI nodes in
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